And at lot of this comes because, as the article says, "us versus them" is a powerful psychological dynamic. Given that that current American society is hyper-competitive, it seems likely this situation will continue. If pulling "us versus them" is akin to chemical warfare - a toxic affair for all concerned that only nets a marginal advantage, it will be used when actual chemical gets used - when one player is losing everywhere and no longer has to care. But that "pulling out all the stops" situation now happens ... always. When will politicians "go the low rout"? Always. When will media? etc.
Which goes back to hyper-competitive. When will it end? I don't know. How will end? Probably in tears but otherwise also hard to say.